This invention relates generally to manufacturing processes for use with semiconductor integrated circuit quad devices and more particularly, it relates to a lead cut and tape attach apparatus for automatically cutting leads of a semiconductor integrated circuit quad device secured to a lead frame on its four sides and subsequently attaching a piece of adhesive tape over the gaps at each of the four sides in a sequential operation.
As is generally known in the art of manufacturing semiconductor devices such as I.C. or "chips," the semiconductor chip or die is secured to a rectangularly-shaped lead frame having a plurality of metal rails or leads extending inwardly from its four sides. The connection of the inner ends of the leads to the semiconductor die is accomplished by a known tape automated bonding procedure. This process serves to establish electrical connection with certain bond areas of the die containing electrical circuits. These I.C. packages (die and lead frame) are then usually delivered to various locations for subsequent processing before they are finally assembled into end products, such as PGA (pin grid array) packages. Such processing would typically include testing of the I.C. packages by attaching selected leads to appropriate testing equipment and measuring the operation of the electrical circuits. However, since all of the leads are joined together on the four sides by the lead frame, which serves to hold and protect the semiconductor die from damage during handling, this has rendered the I.C. packages somewhat unsatisfactory when it comes to testing them.
As a result, there has arisen a need for cutting or severing the leads on the four sides of the semiconductor I.C. package so as to permit testing of the same. However, this will require the use of costly carriers for holding the individual I.C. devices for the testing process and for protecting the leads from deformation since they have been separated from the lead frame.
It would therefore be desirable to provide an apparatus for automatically cutting leads of a semiconductor I.C. quad device secured to a lead frame on its four sides and subsequently applying a piece of adhesive tape over the gaps so as to maintain rigidity between the quad device and the lead frame. It would also be expedient to provide such apparatus which would cut the leads and thereafter apply a tape over the gaps at each of the four sides of the quad device in a sequential operation. As a result, the leads of the quad device being severed from the lead frame and then taped over serves to facilitate the subsequent testing process. This procedure has now eliminated the need of costly carriers for the testing process since the quad device is still joined mechanically to the lead frame. Thus, the lead frame can still be utilized to protect the leads from being deformed or damaged during other subsequent manufacturing processes.
For purposes of completeness, there is disclosed in U.S. Pat. No. 4,683,023 issued on July 28, 1987, to Paul J. Sokolovsky and assigned to the same assignee of the present invention a tape attach machine which includes a punch assembly for cutting and applying adhesive material onto the ends of a semiconductor device package. This '023 patent is hereby incorporated by reference. However, applicants are unaware of any known apparatus that is available for carrying out the cutting of the leads of a quad device and subsequently taping over them on each of the four sides in a sequential operation on an efficient and effective manner. The present invention provides a lead cut and tape attach apparatus which includes a unique indexing means for sequentially applying a piece of overlaying tape to the leads of a semiconductor quad device subsequent to the severing of the leads. The indexing means causes the quad device to be rotated incrementally after each side thereof has had the lead cutting and taping over operation performed.